81654421 has 4 divisors (see below), whose sum is σ = 81811072. Its totient is φ = 81497772.

The previous prime is 81654389. The next prime is 81654431. The reversal of 81654421 is 12445618.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81654421 - 2⁵ = 81654389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81654431) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77541 + ... + 78586.

It is an arithmetic number, because the mean of its divisors is an integer number (20452768).

Almost surely, 2^81654421 is an apocalyptic number.

It is an amenable number.

81654421 is a deficient number, since it is larger than the sum of its proper divisors (156651).

81654421 is a wasteful number, since it uses less digits than its factorization.

81654421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156650.

The product of its digits is 7680, while the sum is 31.

The square root of 81654421 is about 9036.2835834208. The cubic root of 81654421 is about 433.8369796252.

The spelling of 81654421 in words is "eighty-one million, six hundred fifty-four thousand, four hundred twenty-one".